This article proposes a distributed admission control (AC) model
based on on-line monitoring to manage the quality of Internet
multimedia services and Service Level Specifications (SLSs).

The AC strategy covers intra and inter-domain operation, controls
quality-of-service (QoS) without adding significant complexity to
the network control plane and involves only edge nodes. The model
underlying idea is to take advantage of the need and feedback of
systematic on-line QoS monitoring in class-of-service (CoS) networks.
While ingress nodes perform implicit or explicit AC resorting to
service-oriented rules for SLS and QoS parameters control, egress
nodes collect service metrics providing them as inputs for AC. The
end-to-end approach is viewed as a cumulative and repetitive process
of AC and available service computation. The AC criterion is evaluated
as regards its capacity to ensure service commitments while achieving
high network utilization.

The results show that the proposed model provides a good compromise
between simplicity, service guarantee levels and network usage, even
for services with strict QoS requirements. In addition, the QoS
monitoring process is evaluated concerning its ability to capture
the real behavior of each class. Crucial aspects of the model
interrelated areas and implementation key points are also discussed.